Epilepsy surgery
Epilepsy Surgery
The Epilepsy Unit of the Ruber Internacional Hospital began its activity in 1998. Directed by Dr. Antonio Gil-Nagel, during these years it has been able to diagnose and treat hundreds of children and adults, from Spain and also international patients who have come to our center looking for the best care.
Over the years, and adapting to the needs of our patients, the Epilepsy Unit grew to become the current Epilepsy Program. Faced with the increasing number of surgeries performed and wanting to offer the best service in 2020 we created the Epilepsy Surgery Unit.
TECHNIQUES WE PERFORM
The following techniques are performed in the Epilepsy Surgery Unit:
Disconnection by endoscopy
Deep electrodes (thermocoagulation and stereo EEG )
Deep brain stimulation
Electrical stimulation by stimulation of the vagus nerve.
Hemispherectomy
Functional hemispherectomy
Temporary lobectomy
Gamma radiosurgery
Extratemporal resection
Laser thermoablation
What does epilepsy surgery consist of?
The surgical techniques used in this type of surgery are aimed at eliminating the epileptic focus or preventing the spread of epileptic discharges. Patients with epilepsy that is not controlled by drugs (known as refractory or drug-resistant epilepsy) may benefit from these techniques. The location and size of the focus will determine whether curative epilepsy surgery can be performed with a 70/80% chance of seizure control, or palliative surgery that does not completely eliminate the focus, but may offer an improvement in seizure frequency and severity, allowing a reduction in medication and quality of life for patients and their families.
In which cases is epilepsy surgery recommended?
Epilepsy surgery is recommended in patients whose seizures are not controlled after trying at least two antiepileptic drugs. In these cases it is advisable to assess the type of epilepsy and see if they are candidates for epilepsy surgery.
At what age should epilepsy surgery be performed?
We recommend considering surgery after trying two antiepileptic drugs without success. This is the recommendation of the International League Against Epilepsy and other scientific organizations.
Childhood epilepsies:
When dealing with childhood epilepsies, surgery should be considered at a very early age. In this way, children with focal epilepsy can benefit from seizure control and a reduction in medication, both of which facilitate the child’s neurodevelopment and hinder a possible residual neurological deficit, as a consequence of the effect of repeated seizures and high doses of medication.
Surgery may be the solution for childhood epilepsies such as:
- cortical dysplasias
- cortical dysplasias
- focal infantile spasms
- congenital infarction
- malformations of cortical development
- continuous wave point during slow sleep (POCS) of focal origin.
- sequelae of encephalitis
- head injury
- dysembryoplastic neuroepithelial tumor (DNET)
- benign tumors
Epilepsies in adults:
In the case of epilepsies in adult patients, the surgical option should be taken into consideration in both long-standing epilepsies and those of recent onset.
In some patients surgery has not been possible in the past, but we now have new diagnostic and treatment techniques that can determine the location of the focus and control of the seizures. In these cases a surgical evaluation would be advisable.
There is no age limit to undergo this type of surgery; this type of technique has been successfully performed on patients over 60 years of age.
What results can be expected from epilepsy surgery?
In those cases in which the epileptic focus can be localized and completely removed: 8% of these patients achieve complete control of their seizures.
If the location of the focus is less precise or the lesion is extensive: seizure control can be achieved in 40/50% of patients. Surgery offers an improvement in quality of life and a reduction of the effects of high medication.
Indications for epilepsy surgery
A. Minimally invasive surgeries
Stereo electroencephalography deep electrodes and thermocoagulation. It is applied in patients with visible or non-visible lesion on MRI(focal epilepsy with negative MRI or epilepsy with normal MRI). It is an essential technique when the brain MRI does not show the lesion, i.e., it is reported as normal or is doubtful. Several deep electrodes directed to the focus are introduced and maintained for 3 to 5 days, while the patient remains in the video-EEG monitoring unit. With this technique, epileptic activity is recorded with maximum precision. The same deep electrodes are used to cauterize the epileptic focus identified during the recording with an electric current. The procedure begins with a thorough review of symptoms, EEG, MRI, PET and MEG findings. From this review, planning is carried out in a three-dimensional coordinate system. In the operating room under general anesthesia the electrodes are inserted with millimeter precision in the selected areas. Once the patient is awake, he is transferred to the epilepsy and video-EEG unit where his epileptic seizures are recorded, their location is mapped and the area with epileptic activity is thermocoagulated. The electrodes are usually removed in 4 or 5 days after the procedure is completed. The probability of control or very significant improvement depends on the extent of the epileptic focus: in patients with small lesions the probability of seizure control is 80%. In patients with large lesions the propagation pathways are reduced and the chances of complete control are lower, but the vast majority have a very significant improvement. Surgery improves quality of life, and makes it possible to reduce antiepileptic medication and sometimes to discontinue it.
- Focal epilepsy with normal MRI
- Hippocampal sclerosis
- Temporal epilepsy
- Extratemporal epilepsy: frontal, parietal and occipital.
- Cavernous angioma
- Cortical dysplasia
- Tuberous sclerosis
- Dysempbryoplastic neuroepithelial tumor
- Hypothalamic hamartoma
- Ganglioglioma, gangliocytoma
- Low-grade astrocytoma associated with epilepsy
Traumatic injuries
B. Epilepsy surgery by craniotomy
Temporal lobectomy: is one of the most common interventions in epilepsy surgery. It is indicated in patients with medial temporal sclerosis (hippocampal atrophy) and other lesions affecting the temporal lobe.
Extratemporal surgery: indicated in patients with extensive lesions, covering a large part of one or several lobes. Often before surgery it is necessary to explore with deep electrodes and perform thermocoagulation, or to place subdural electrodes to record seizures and map the function of the cerebral cortex.
Indications for epilepsy surgery with craniotomy:
- Dysplasias
- Neuronal migration disorders
- Cavernous angioma
- Temporal encephalocele
- Brain tumors
- Brain contusion
- Cranioencephalic trauma
- Meningitis and encephalitis
- Cerebral hemorrhage
- Congenital infarction
- Perinatal injuries
Traumatic injuries
HemispherectomyHemispherectomy: It is applied in patients with lesions affecting a large part of a hemisphere. Functional hemispherectomy is usually performed, which is less aggressive than classic hemispherectomy. In general, these are patients with severe epilepsies, who may be receiving a large amount of antiepileptic drugs without appreciating a clear improvement, and often suffer from deficits in movement of the limbs corresponding to the diseased hemisphere. In children, in order to improve neurodevelopment, it is advisable to perform them early, when there is evidence that epilepsy is not controlled with medication.
Indications for hemispherectomy:
- Rasmussen syndrome
- Congenital hemiplegia
- Perinatal infarction
- Hemimegalencephaly
- Sturge-Weber syndrome
- Extensive cortical dysplasia
- Malformations of cortical development
- Sequelae of encephalitis
- Sequelae of brain tumor surgery
- Radiotherapy sequelae
- Cranioencephalic traumas
How does an Epilepsy Surgery Team work?
Epilepsy surgery offers excellent results when it is well indicated and performed. An exhaustive and meticulous study is necessary to ensure a correct indication and localization of the focus. This type of surgery should be performed in specialized centers with professional teams that have extensive experience and cover various disciplines with research and scientific activity offering the latest techniques and advances.
The Epilepsy Surgery Unit of the Ruber International Hospital has a team of neurologists, neurosurgeons, neurophysiologists, neuropsychologists and nurses specialized in epilepsy with extensive experience.
Pre-surgical evaluation
In order to perform a pre-surgical evaluation, an exhaustive epilepsy consultation is required. The patient’s clinical history, response to medication, history, family history, genetic factors that may influence, symptoms during seizures, the impact of the disease and treatment on quality of life are studied. This first contact is made in a consultation lasting one hour, which is completed with subsequent calls, review of tests and previous reports.
Once this first history has been completed, it is necessary to perform some specific tests:
1. Video EEG monitoring (video electroencephalography, video-EEG monitoring, video-EEG telemetry)
Video electroencephalographic monitoring(video-EEG, video-EEG monitoring, video-EEG telemetry): prolonged EEG identifies epileptiform changes not usually seen in short studies (such as routine EEGs and sleep EEGs). This test allows us to observe the clinical manifestations associated with EEG changes. With the reading of the records we will know if the problem is an epilepsy, of what type (focal or generalized) and we will be able to obtain an approximate location of the epileptic foci.
A video EEG can have a variable duration (24h to 5 days). In some cases the medication is partially or completely withdrawn.
2. MRI and MRI: Magnetic resonance imaging of the brain or magnetic resonance imaging.
In order to get the most out of this type of test, the studies must be of the highest quality, with specific protocols, performed by specialized neuroradiologists and sometimes they must be completed with new studies. Identifying a lesion in an MRI image facilitates the localization of the epileptic focus. Sometimes an MRI may appear normal but this is not a reason to rule out surgery. It is common for patients to say that their epilepsy cannot be operated on because no lesion was located after an MRI.
Thanks to years of experience and the most advanced stereo-EEG and image post-processing techniques, we can locate the epileptic focus and assess the possibility of surgery. Magnetic Resonance Imaging may also be necessary to study the cerebral communication pathways (tractography) and the functional localization of language, movement, vision, etc.
3. PET (brain): Positron Emission Tomography.
Brain PET allows the study of brain metabolism. A decrease in glucose metabolism usually shows the epileptic focus. Sometimes a PET can be reported as normal, but a targeted examination of the area of interest allows us to identify subtle alterations, but PET can also show extensive alterations,
Other times on the contrary, the PET shows very extensive alterations, which improve when surgery is successful, this shows that the focus is often smaller than it appears on the PET. The fact that a PET scan shows an extensive alteration should not be a reason to rule out possible epilepsy surgery.
4. MEG: Magnetoencephalography
This technique allows us to study the magnetic fields of the cerebral cortex, it is a valuable non-invasive technique to localize the focus. Thanks to MEG we can improve the precision of the resection and the placement of deep electrodes.
5. Deep and subdural electrodes
We perform these studies when previous techniques reveal the approximate location of the focus.
Multidisciplinary clinical session
After the patient’s study, our team meets to evaluate the case.
We bring together the entire team, adult and child neurologists specialized in the diagnosis and treatment of patients with epilepsy, neurophysiologists, nurses and neuropsychologists. We also like to include the referring physician.
We determine the possibility of surgery, what would be the most appropriate intervention and the minimum effective resection to be performed, in order to preserve intact neurological function. We always give priority to minimally invasive interventions. By being able to carry out the techniques and research in our Center, it is possible to optimize the surgical indications while maintaining the principle of performing the minimum possible resection but optimizing the chances of controlling epilepsy.
Once it has been decided that the patient is a candidate for surgery and the approach, surgery can be performed in the following days or weeks, without unnecessary delays, since repeated seizures can only increase the risk of brain damage, so it is important to apply solutions early. In some cases, medication changes are made before surgery to facilitate the postoperative period or to avoid problems such as excessive bleeding during surgery.
In patients treated by stereo-EEG and thermocoagulation we can optimize the result by increasing the number of electrodes directed to the epileptogenic zone. Sometimes it is necessary to repeat the procedure a few months later to improve seizure control. On other occasions stereo-EEG provides the limits of a resection to be performed later by craniotomy. In our center, as has been described in other international centers, patients who improved with thermocoagulation but were not fully controlled may especially benefit from subsequent curative surgery; an initial favorable response to thermocoagulation, even in cases with normal MRI, supports resection with curative intent.
